What the scores actually mean for patients

For most patients, the central question is straightforward: do the benefits from ChondroFiller last? Based on published evidence at three to five years, the answer is broadly yes — for suitable patients, within the studied timeframe, meaningful symptom relief is sustained in around 70–85% of treated cases across multiple independent cohorts, not a single sponsored trial.

Two scoring tools underpin that conclusion. The IKDC Subjective Knee Score is a patient-reported measure — 18 questions covering symptoms, daily activities, and sport — that tracks what people actually feel and can do. The MOCART score is MRI-based, grading how well the repaired tissue has filled and integrated structurally at the defect site. Together they capture both the lived experience and the structural picture, which is why clinicians use them in parallel rather than relying on either alone.

It is important to be precise about the quality of this evidence. The studies available are observational cohorts and post-market clinical follow-up programmes, not large randomised controlled trials. That distinction matters for realistic expectations. ChondroFiller is CE-marked in Europe and has been in clinical use since 2013; it does not hold FDA approval, so findings from any US-based data are not directly applicable here. The sections that follow are specific about what the evidence shows — and where the gaps remain.

IKDC scores in the knee: what three years of data shows

The headline figure from the Jerosch post-market clinical follow-up (PMCF) study — currently the longest published knee-specific dataset — is a mean IKDC improvement of 32.4 points, sustained and marginally higher at the three-year mark. Patients began with a baseline score of approximately 48, reaching roughly 80 at three years. To put that in context: the minimum clinically important difference (MCID) for the IKDC is 16.7 points — the threshold at which patients typically notice a meaningful difference in daily function, not merely one detectable on a scale. A 30-point gain is roughly double that figure. This matters because it moves patients from the territory of significant limitation into a range where activities such as walking, stair-climbing, and recreational exercise become meaningfully more manageable.

Across four independent published knee cohorts, the average IKDC improvement converges on approximately 30 points from a similar starting baseline of around 48. Convergence across independent sources — rather than a single sponsored study — gives that number reasonable weight within the observational evidence available.

Simeonov et al. (Journal of IMAB, December 2024; n=17, mean age 31) adds an important timing nuance. Significant IKDC and Lysholm score improvements were recorded at three, six, and twelve months, but there was no statistically significant difference between the six- and twelve-month readings. In practice, this suggests that most functional recovery consolidates within the first six months; what follows appears to be structural maturation of the regenerated tissue rather than further functional leaps.

A plateau in functional scores is not the same as regression. The Jerosch data show that scores are sustained — and marginally improve — out to three years. What the evidence does not yet establish is whether this stability continues beyond that window in the knee; no published knee dataset extends further.

MOCART scores: the structural picture on MRI

MRI provides the structural counterpart to the functional scores patients report. MOCART — a 0–100 scale used by radiologists to grade how well a cartilage repair site has filled, integrated at its margins, and matured in signal quality — lets clinicians track what is happening inside the joint, independent of what patients feel on any given day.

The trajectory after ChondroFiller injection follows a predictable arc. At four weeks, MOCART scores average around 65.3, reflecting early scaffold establishment rather than completed repair. By one year, scores reach 81.6 in a key longitudinal dataset; European follow-up data report a stable range of 81.6–84.3 at later time points. A score above 80 corresponds to greater than 80% defect fill with good peripheral integration — the structural basis for the functional recovery described in the IKDC data from the preceding section.

Stability in that 81–84 range represents consolidation, not stagnation. The scaffold has done its job: through acellular matrix-induced chondrogenesis, it supports the body's own repair processes by recruiting the patient's own progenitor cells from surrounding synovium and subchondral bone. What fills the defect is fibrocartilage — primarily Type I collagen — rather than the original hyaline cartilage. Fibrocartilage is durable and biomechanically functional in daily use, but it is structurally distinct from native articular cartilage and carries different load-bearing characteristics. That distinction is worth stating plainly: the repair is meaningful and, on current evidence, lasting — but it is not identical to the joint surface the patient started with.

Five-year durability: what the hip cohort data shows

The question that tends to surface once patients have absorbed the one- and two-year data is a different one: not whether ChondroFiller works initially, but whether it keeps working. The only published dataset reaching five continuous years of follow-up is the Mazek 2021 hip cohort — a study of 26 patients, 21 of whom were evaluable at extended follow-up — and its central finding is that 17 of those 21 patients (81%) maintained good or excellent outcomes at the three-, four-, and five-year time points simultaneously.

What makes that figure useful is the consistency across years rather than a single end-point snapshot. Sustained benefit at each annual mark, rather than a declining slope that happens to remain acceptable at year five, suggests the repair is holding rather than gradually eroding.

The caveat is important and should not be glossed over: this is a hip cohort. The joint environment, loading patterns, and defect geometry differ from the knee, and the Mazek data cannot simply be applied to knee outcome expectations. Knee-specific follow-up currently extends to three years — the functional and structural picture at that point is covered in the preceding sections — but beyond that window, no published knee dataset yet exists. That gap is acknowledged plainly here rather than papered over with inference.

Who gets the best results: patient selection and realistic expectations

Patient selection, more than any other variable, determines where an individual sits within that 70–85% success range. The evidence base is built on a specific profile: younger, active patients with focal, contained chondral defects — discrete areas of full-thickness cartilage loss rather than widespread joint deterioration. For that group, the functional and structural outcomes described in preceding sections are a realistic frame of reference.

At the other end of the spectrum, advanced generalised osteoarthritis is a clear contraindication. Clinicians use established grading systems — Kellgren-Lawrence (typically grades III–IV in the knee) and Tönnis (grades 2–3 in the hip) — to assess the extent of joint involvement at the point of assessment. Patients do not need to memorise those scales, but knowing they exist is reassuring: suitability is determined by structured clinical and imaging criteria, not guesswork. Where the broader joint environment is too compromised, the scaffold has no stable substrate to work with, and outcomes in that group are poor.

For patients wondering how ChondroFiller compares with microfracture — a common question — the honest answer is that published success rates are broadly similar. No large-scale randomised controlled trial has demonstrated superiority in either direction. The meaningful distinction is the delivery route: ChondroFiller is placed under ultrasound guidance in an outpatient setting, without the recovery burden associated with more invasive procedures. The safety profile supports that framing: serious adverse events occur in approximately 0% of reported cases, and the reoperation rate of 3–8% sits well below that of surgical cartilage repair alternatives.

Booking an assessment at London Cartilage Clinic

Whether the evidence profile outlined here applies to a specific joint, defect size, and activity level is a question that requires a proper clinical assessment rather than a self-referral decision. That assessment — reviewing imaging, defect geometry, and the patient's own functional goals against the criteria the data supports — is where the scores discussed in this article become practically useful rather than simply informative.

At London Cartilage Clinic's Harley Street practice, ChondroFiller is delivered as an ultrasound-guided outpatient injection for suitable focal cartilage defects, within a pathway designed to avoid surgical admission and its associated recovery burden.

To discuss whether this approach aligns with your situation, book a consultation at londoncartilage.com.